Art of coloring wood.



- appearance and texture.

UNITED STATES r E r' OFFICE.

WILLIAM/AUGUSTUS HALL, OF NEW YORK, N. Y.,, ASSIGNOR TO AMERICAN MAHOGANY COMPANY, A GORPOKATIONOF MAINE.

ART 'OF" COLORING WOOD.

Specification of Letters Patent;

Patented Oct. I3, 1908.-

Application filed. June 29,1906. Serial No; 324,027.

ings.

This invention has for its object to produce, from acomparatively inexpensive wood, a product closely resembling mahogany or-other high-priced wood, both inits This object is accomplished by a novel. treatment of an in-. expensivewood'so asto give-it the appear ance and texture, throughout its body, of the more-costly wood.

Attempts have heretofore been made toproduce'imitations of' mahogany and other high priced woods," from less expensive hard woods, by forcing astaining dye or liquid 1nto the comparatively cheap woods; but-inorder to secure satisfactory results, by the rocesses heretofore employed, it has been ound necessary, in forcing the coloring solutions into the Wood, to use exceedingly high pressures, of from 800 to 1000 pounds to the square inch, or thereabout. Such high pressures have required very strong and costly tanks or cylinders of comparatively smal diameters and capacities, so that the process of stainingthe wood has been so slow and costly that it has never gone into commercial use, to any considerable extent, so far as I am informed.

My invention has for its object to over-. come the difficulties heretofore encountered by a process which will enable the use of comparatively small amounts of coloring matter, and which can be carried into efiect by the use of tanks or pressure cylinders of much greater capacity and lower cost than those heretofore required; in that the wood 1s first softened and itsfibers somewhat loosened or opened, and is also largely stained or darkened to a brownish red by'a cooking process; is then rendered absorbent by a suction pi'ocess which exhausts the liquor or water om thewood, and the wood is then further stained or darkened and'it's grain develo ed by forcing liquid coloring matter into t e same; and this, owing to the' absorbent condition of the wood, can be carried into efiect azt comparatively: low pressures and-in: tan-ks orireceptacles much larger and less expensive than those heretofore required where *extreinelyhigh. pressures for foreingthe coloring or staining materials into the wood were necessary.

In carrying-the invention into effect l take a hard wood (preferably yellow birch) in the form of deals, planks, boards or otherwise, and cook the same, by boiling in water in a closed tank orzre'ceptacle under: a steam pressure of approximately 30 to 45 pounds pressure to the" square inch, thus securing cooking temperatures-of from-about 250 to 275 F. This cooking. operation is continued fromone to three orf'our hours, according to the thickness: o'f the wood, or-untilthe resinous and gelatinous properties of the woodare thoroughlysoftened: and-the fiber of the wood somewhat loosened. This boiling or. cooking, at the high temperatures referred to, also gives to the-wood-a reddish orbrownish color which results from a stain due probably to a change inthe ligno-cellu'lose-compounds of the wood. The wood is then subjected to suction in .a vacuum tank or chamber from which the air may be so far exhausted that the suction will draw the liquor or water out of the wood, so far as is practicably possible, so as to leave the wood in a more absorbent condition than it otherwise would be. After the wood has been thus rendered absorbent, and for the pn ose of further coloring the same, a suitable iquid coloring matter, which will preferably contain salts of tannin and logwood or hemlock extract, is then put into the tank in which the wood is inclosed, and is forced into the ores of the wood preferably by a high hy raulic pressure; this operation being contmued until the wood is impregnated with the coloring matter to such a dc ree that when the wood is dried it will close y resemble mahogany or other high priced wood, both in appearance and texture, according to the character of the staining material used for coloring or: darkening the same. In this coloring rocess more of the coloring matter is absor ed in the lines largely due to the fact that the vacuum fected, as the wood will be partly colored by the cooking process and can then be colored to the desired dark shades by a comparatively small amount of the stains or dyes.

So far as has been shown by the experiments which have been madein this matter,

yellow birch is the most suitable hard wood for being converted into imitation or artificial mahogany by the process above described, in that the grain or texture of this wood, after having been subjected to the described process, is almost identical with the grain or texture of real mahogany. Other hard and comparatively inexpensive woods may, however, be subjected to the same treatment, without departing from the invention, and similar results be thereby secured. 7

Having thus described my invention or discover I claim and desire to secure by Letters atent:

1. The herein described process of producing imitation of high-priced woods, consisting incooking a comparatively inexpensive wood in water and at a temperature or temperatures exceeding 240 F. until the same is stained or darkened, then subjectin the wood to a vacuum process so as to sucr the water out of the wood so far as possible, and then further coloring or darkenln the Wood and develo ing the grain thereof y forcing a liquid coloring matter into the wood by pressure in a closed receptacle.

2. Theherein-described process of producing imitation of high-priced woods, consisting in cooking a comparatively inexpensive wood in water; and at a temperature or temperatures exceeding 240 F. until the gelatinous and resinous propertiesCthereof are softened and the, wood is darkened throughout, then subjecting the wood to a vacuum process for the pu ose of sucking the liquid out of the wood so ar as possible, and finally im regnating the wood, thus rendered absor ent by the vacuum process, with a liquid coloring matter which is forced into the wood under pressure so that the coloring matter becomes largely deposited in the annular rings and grain cells, thereby intensifying or developing the rain of the wood.

In testimony w ereof I afiix my signature, in presence of two witnesses.

WILLIAM AUGUSTUS HALL.

Witnesses:

HENRY OALvER, O. M. SWEENEY. 

